This invention relates to the manufacture of thermoplastic resin sheet material such as vinyl coated fabrics, expanded vinyl sheet and other plastic roll goods. More particularly, the invention relates to the reclaiming or reprocessing of scrap material produced in the manufacture of various plastic roll goods, especially scrap that contains reinforcing textile fabric.
Enormous amounts of scrap are generated during the manufacture of textile fabric reinforced thermoplastic resin sheet material (hereinafter "reinforced sheet"). This scrap includes, for example, selvedge trim--strips trimmed from the sides of a long sheet to eliminate edge irregularities and to provide the desired lateral dimension. This scrap is difficult to dispose of and usually requires the services of an industrial waste contractor. This service is costly, particularly because space for such disposal is increasingly difficult to find.
While thermoplastic sheet material that has no textile fabric reinforcement may be readily reprocessed merely by mixing the scrap with virgin material and processing it according to standard practices, these same techniques cannot be readily adapted to scrap from reinforced sheet because of the fabric backing. The woven fibers prevent the material from banding on a mill and thus it cannot be calendered.
Certain methods have been developed for reprocessing scrap from reinforced sheet by chopping it into small pieces and then removing altogether a substantial amount of the textile fibers, such as by a vacuum process as disclosed in U.S. Pat. No. 3,562,373 of Logrippo. These methods are costly and time-consuming, however, and they in turn also produce scrap in the form of the removed textile fibers that must be disposed of. Accordingly, they are not feasible from an economic point of view and do not completely eliminate the problem of disposal.
The method and apparatus of the present invention, however, reduce the difficulties indicated above and afford other features and advantages heretofore not obtainable.